Thioacetamide is a commercially available chemical having many industrial uses and is a versatile reagent for further chemical synthesis. The reaction of hydrogen sulfide and acetonitrile to produce thioacetamide is well known. U.S. Pat. No. 2,421,031 discloses the use of a catalyst, 8-14 mesh SiO.sub.2 Al.sub.2 O.sub.3 gel, at a temperature of about 500.degree. F. to obtain yields of 85% based on hydrogen sulfide. The reaction is also catalyzed by various bases. Jaworski, et al., disclosed the use of triethylamine in a 220-hour reaction carried out in benzene or toluene (Polish J. Chem., 52 (10): 2067-8, 1978). Girgis disclosed the use of amine catalysts, including secondary amines (Canadian Pat. No. 946,392, 1974; U.S. Pat. No. 3,852,287, 1974; U.S. Pat. No. 3,700,664, 1972). More recently, alkyl metal sulfides and hydrosulfides have been disclosed as catalysts for the reaction of aminonitriles with hydrogen sulfide for the production of aminothioacetamides (Moder et al., EP 0 272 909). Moder et al. prefer these catalysts because the amine base catalysts previously used are difficult to remove after completion of the reaction.
It is an object of the present invention to provide a high-yielding, cost-effective process to prepare thioacetamide with minimal post-reaction processing and reusable catalysts.